initial code commit

src/statfs.cpp

@@ -0,0 +1,160 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <fuse.h>
+
+#include <sys/statvfs.h>
+#include <errno.h>
+
+#include <climits>
+#include <string>
+#include <vector>
+#include <map>
+
+#include "ugid.hpp"
+#include "config.hpp"
+
+using std::string;
+using std::vector;
+using std::map;
+using std::pair;
+using mergerfs::Policy;
+
+static
+void
+_normalize_statvfs(struct statvfs      *fsstat,
+                   const unsigned long  min_bsize,
+                   const unsigned long  min_frsize,
+                   const unsigned long  min_namemax)
+{
+  if(fsstat->f_bsize > min_bsize)
+    {
+      fsstat->f_bfree  *= fsstat->f_bsize / min_bsize;
+      fsstat->f_bavail *= fsstat->f_bsize / min_bsize;
+      fsstat->f_bsize   = min_bsize;
+    }
+
+  if(fsstat->f_frsize > min_frsize)
+    {
+      fsstat->f_blocks *= fsstat->f_frsize / min_frsize;
+      fsstat->f_frsize  = min_frsize;
+    }
+
+  if(fsstat->f_namemax > min_namemax)
+    fsstat->f_namemax = min_namemax;
+}
+
+static
+void
+_merge_statvfs(struct statvfs       * const out,
+               const struct statvfs * const in,
+               const Policy::StatFS         policy)
+{
+  switch(policy)
+    {
+    case Policy::StatFS::SumUsedMaxFree:
+      if(out->f_bfree < in->f_bfree)
+        {
+          out->f_bfree  = in->f_bfree;
+          out->f_bavail = in->f_bavail;
+        }
+      break;
+
+    default:
+    case Policy::StatFS::SumUsedSumFree:
+      out->f_bfree  += in->f_bfree;
+      out->f_bavail += in->f_bavail;
+      break;
+    }
+
+  out->f_ffree  += in->f_ffree;
+  out->f_favail += in->f_favail;
+  out->f_files  += in->f_files;
+  out->f_blocks += in->f_blocks;
+}
+
+static
+int
+_statfs(const Policy::StatFS  policy,
+        const vector<string> &srcmounts,
+        struct statvfs       &fsstat)
+{
+  unsigned long min_bsize   = ULONG_MAX;
+  unsigned long min_frsize  = ULONG_MAX;
+  unsigned long min_namemax = ULONG_MAX;
+  map<unsigned long,struct statvfs> fsstats;
+  vector<string>::const_iterator iter;
+  vector<string>::const_iterator enditer;
+
+  for(iter = srcmounts.begin(), enditer = srcmounts.end(); iter != enditer; ++iter)
+    {
+      int rv;
+      struct statvfs fsstat;
+      rv = ::statvfs(iter->c_str(),&fsstat);
+      if(rv != 0)
+        continue;
+
+      if(min_bsize > fsstat.f_bsize)
+        min_bsize = fsstat.f_bsize;
+      if(min_frsize > fsstat.f_frsize)
+        min_frsize = fsstat.f_frsize;
+      if(min_namemax > fsstat.f_namemax)
+        min_namemax = fsstat.f_namemax;
+
+      fsstats.insert(pair<unsigned long,struct statvfs>(fsstat.f_fsid,fsstat));
+    }
+
+  map<unsigned long,struct statvfs>::iterator fsstatiter    = fsstats.begin();
+  map<unsigned long,struct statvfs>::iterator endfsstatiter = fsstats.end();
+  if(fsstatiter != endfsstatiter)
+    {
+      fsstat = (fsstatiter++)->second;
+      _normalize_statvfs(&fsstat,min_bsize,min_frsize,min_namemax);
+      for(;fsstatiter != endfsstatiter;++fsstatiter)
+        {
+          _normalize_statvfs(&fsstatiter->second,min_bsize,min_frsize,min_namemax);
+          _merge_statvfs(&fsstat,&fsstatiter->second,policy);
+        }
+    }
+
+  return 0;
+}
+
+namespace mergerfs
+{
+  namespace statfs
+  {
+    int
+    statfs(const char     *fusepath,
+           struct statvfs *stat)
+    {
+      const ugid::SetResetGuard  uid;
+      const config::Config      &config = config::get();
+
+      return _statfs(config.policy.statfs,
+                     config.srcmounts,
+                     *stat);
+    }
+  }
+}